1. Field of Invention
This invention relates to atmospheric liquid heaters; and, more particularly, to portable atmospheric heaters having improved startup, shutdown and recirculating performance for more efficiently providing super-heated aqueous solutions.
2. Description of Related Art
In cooler climes, such as the northern and southern regions of the globe, as well as at high altitude, such as in the Rocky Mountain areas, portable heating devices are often needed. Although there are many portable heaters in many aspects, these heating systems suffer from one or more problems which render them deficient in supplying the quality and quantity of heated liquid required. While a number of pressurized boilers for providing heated steam/water mixtures exist, they are somewhat complicated, require pressurized vessels, and are expensive to build and maintain. Additionally, housing pressurized vessels, pump valves, and the like become somewhat difficult if the system needs to be mobilized, especially in mountainous areas with inferior roads and limited access to the specific areas in which the systems are to be utilized.
One of the problems with most atmospheric boilers is that, as the altitude increases, the temperature at which the liquid boils decreases. Thus, in order to achieve elevated liquid temperatures at atmospheric pressure, it is frequently necessary to employ boiling point elevators to increase the liquid temperature at which the liquid boils. These substances can cause corrosion as well as limit the use of the boiler system. For example, heated pure water is necessary for field showers and the like, but, in such cases, boiling point enhancers may be toxic and, therefore, cannot be used.
Additionally, at high altitude or in northern climates, melting snow or thawing the ground is required, for example, to dig trenches or foundations, lay wire, pipe-cure concrete, and the like during the winter months. Further, in these climes, a portable heating device is necessary to remove ice and snow from, for example, shelters and sheds nestled in mountainous terrain. Finally, portable heating devices are needed for the construction of buildings, houses, and the like in remote, inclement locations, so that workmen can enjoy a conducive work environment free from the mobility constraints imposed by the need for multi-layered clothing.
Heretofore, a number of devices have been available to do one or more of the aforementioned tasks, but none have been versatile enough to meet all of the above needs adequately. For example, U.S. Pat. No. 5,181,655, for a "Mobile Heating System" issued to Mark Bruckelmyer on Jan. 26, 1993, provides for a mobile heating system used to thaw the ground in preparation for construction. The disclosed heating system involves pumping heated water from a reservoir through hosing to a plurality of elongated boiler probes which are driven into the ground, or whatever substance needs to be thawed. Generally, this patent discloses a heating system for thawing frozen ground or building materials, such as bricks. The invention includes a boiler for heating fluid which is circulated by a pump through a connected line which is in fluid communication with a plurality of elongated heater probes adapted to be implanted in the ground. An antifreeze reservoir is connected to the line for pumping antifreeze into the line to protect it and the probe from freeze-damage when not in use. This system has a number of draw-backs, including the necessity of driving the heating probes into the frozen earth.
Likewise, U.S. Pat. No. 5,567,085, for "A Method of Thawing Frozen Ground for Laying Concrete" issued to Bruckelmyer on Oct. 22, 1996, uses a circulation hose that is covered with an aggregate and placed into a form from which concrete is poured. In one embodiment, the hot fluid circulating within the aggregate-covered hose becomes a part of the concrete structure, and the hose is severed at its exit point from the concrete forms. The disclosed method involves placing a continuous length of circulating hose on the frozen ground, either inside or adjacent to the concrete form where the concrete is to be poured, and then covering the hose with a layer of aggregate material for insulation. In one aspect, this method invention is for circulating warm liquid through a circulating hose inserted into poured concrete to prevent freezing while the concrete hardens. A disclosed advantage is that this method of thawing frozen ground to lay concrete does not require removal of the hose prior to actually laying the concrete.
Neither of these systems employ a booster recirculating-type reservoir system to provide high heat gain, fast recovery and high heat capacity for incrementally super-heating the aqueous liquid before it is returned to the system. In addition, these systems are not designed for high-capacity water needs, such as providing hot water for field showers or for other hygienic purposes, such as forestry services, and the like. Thus, it would be advantageous to have a high-capacity, atmospheric, transportable system to provide hot water and heat to remote and undeveloped sites, such as locations that are under construction or in developmental stages, whether the need was for space heating, drying and curing concrete, plaster, or paste, or the like, or for simply melting ice and snow and thawing earth in preparation for forms, or for laying wire, conduit pipe, and the like.
U.S. Pat. No. 4,491,113, for a "Probe for Circulating Heated Water" issued to Mark Bruckelmyer on Sep. 12, 1995, generally discloses an insertable thawing probe as a portion of a mobile heating system which circulates heated water and thaws frozen ground. The probe includes a T-connection having both a fluid inlet section and a fluid outlet section. The probe is generally used for insertion into frozen ground for thawing areas proximate to frozen sewer or water lines.
In very cold climates, bringing the temperature of the circulating fluid up to the required temperature is time consuming and requires substantial amounts of energy. The systems that provide for the circulation of heated liquids throughout the thawing circuit described above require the entire body of liquid to return to the boiler to be heated.
It would be advantageous to have a high heat capacity, atmospheric heating system wherein the liquid could be brought to temperature without use of hose shunts or the like. In accordance with the heater disclosed in my prior application, which, as stated above, is incorporated by reference herein in its entirety, two short lines were used to connect the exit and return manifolds to preheat the system by circulating the fluid through the entire system. It would therefore be advantageous to have a liquid heater with a preheating circuit which bypasses the entire system during idle or startup. It would also be advantageous to have a flushing system which clears out the lines without requiring the user to handle a wet flushing tool.